Prescription-even monitoring

A British study conducted on the basis of prescription-even monitoring (PEM) involved cohorts exceeding 10,000 patients for paroxetine, fluvoxamine, sertraline, and fluoxetine (Mackay et ah, 1997). The study confirmed the general similarity of reported adverse events, with two possible exceptions Fluvoxamine (Luvox) had an increased number of reported adverse events, and paroxetine (Paxil) had an increased number of reported withdrawal reactions. 

Certainly Richard raises valid points, and you can hardly fault his prescription for monitoring and improving the results. However, is that considered, or should that be considered a requirement for validation, or even a necessary part of the validation process The response comment to Richard at the time was as follows ... 

The interaction between warfarin and cimetidine is well documented, well established and potentially clinically important. Its effects are generally modest, but rarely, patients have shown a marked interaction. Because of this unpredictability, and to avoid bleeding, the response should be monitored well in every patient when cimetidine is first added, being alert for the need to reduce the warfarin dosage. The onset of the interaction appears rapid effects have been seen within days, and even as early as 24 hours. The effect of low non-prescription doses of cimetidine on warfarin do not appear to have been studied. Acenocoumarol is reported to in-teraet similarly, and there is one case of phenindione being affected. Expect other coumarins and indanediones to behave in the same way, with the possible exception of phenprocoumon, which was not affected in one study. 

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